ACE1502 Datasheet, PDF (24/33 Pages) Fairchild Semiconductor – Arithmetic Controller Engine for Low Power Applications

Figure 30. Programming Protocol¹³
A
VCC
RESET
T_reset
LOAD (G3)
CLOCK (G1)
32 clock pulses
SHIFT_IN (G4) 1 1 0 1 0 0 1 0 1 1
SHIFT_OUT (G2)
(in write mode)
10-bit Opcode = 0x34B
bit 31
bit 30
SHIFT_OUT (G2)
(in read mode)
A: start of programming cycle
13. During in-circuit programming, G5 must be either not connected or driven high.
Figure 31. Serial Data Timing
t_HI
t_LO
CLOCK (G1)
t_DIS
t_DIH
SHIFT_IN (G4)
Valid
t_DOS
t_DOH
SHIFT_OUT (G2)
Valid
t_ACCESS
11. Brown-out/Low Battery Detect Circuit
The Brown-out Reset (BOR) and Low Battery Detect (LBD)
circuits on the ACEx microcontroller have been designed to
offer two types of voltage reference comparators. The sections
below will describe the functionality of both circuits.
Figure 32. BOR/LBD Block Diagram
+1.8V
Vref
Vcc
0
G4
1S
Adjust Reference Voltage
t_load1 t_load2
bit 0
_
BOR
+
_
LBD
+
t_ready
A _{tload3 tload4}
BUSY low by
2nd clock pulse
BUSY
READY
bit 31
to RESET logic
7
6
5
4
3
2
1
BL[4] BL[3] BL[2] BL[1] BL[0] VSEL
X
0
LBD
LBD
Control
Register
24
ACE1502 Product Family Rev. 1.7
www.fairchildsemi.com